The document outlines the basics of storage technology, detailing the definition, types, and characteristics of storage devices. It classifies storage into primary and secondary types, and further categorizes them into Direct Attached Storage (DAS), Network Attached Storage (NAS), and Storage Area Network (SAN), highlighting their advantages and disadvantages. Additionally, it discusses the evolution of storage technology and the differences between NAS and SAN, focusing on protocols, connections, and performance features.

1. Basics of Storage Technology
Lopamudra Das

2. What is STORAGE ?
• A storage device is any computing hardware that is used for storing, porting and extracting data files and
objects. It can hold and store information both temporarily and permanently, and can be internal or external
to a computer, server or any similar computing device.
• A storage device may also be known as a storage medium or storage media.
• Storage Device
• Storage devices are one of the core components of any computing device. They store virtually all the data
and applications on a computer, except hardware firmware. They are available in different form factors
depending on the type of underlying device.
• Example: RAM, cache, a hard disk, an optical disk drive and externally connected USB drives.
• There are two different types of storage devices:
• Primary Storage Devices: Generally smaller in size, are designed to hold data temporarily and are
internal to the computer. They have the fastest data access speed, and include RAM and cache
memory.
• Secondary Storage Devices: These usually have large storage capacity, and they store data
permanently. They can be both internal and external to the computer, and they include the hard
disk, compact disk drive and USB storage device.

3. Types of Storage…..
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The three fundamental types of storage are….
• DAS (Direct Attached Storage)
• NAS (Network Attached Storage)
• SAN (Storage Area Network)
All three Storage types evolved over the years, Storage requirements and technology
advancement led to one another. In other words DAS led to -> NAS and in turn NAS led to
-> SAN.

4. Types of Storage…
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Typical DAS Storage solution

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Types of Storage….
DAS as its name implies is simply primary storage that is designed to be used by one and
only one computer.
Advantages:
Great for Mainframes and OLTP type high data intensive requirement.
Disadvantages:
DAS cannot share unused resources or data with other servers, and therefore it is also
called island of information.
DAS typically have limited scalability, Server has to be rebooted, creating downtime
during the installation process.

6. Network Attached Storage (NAS)
• NAS is adedicated storage device, and it operates
in a client/server mode.
• NAS is connected to the file server via LAN.
• Protocol: NFS (or CIFS) over an IP Network
– Network File System (NFS) – UNIX/Linux
– Common Internet File System (CIFS) – Windows Remote file
system (drives) mounted on the local system (drives)
• evolved from Microsoft NetBIOS, NetBIOS over TCP/IP (NBT), and Server
Message Block (SMB)
– SAMBA: SMB on Linux (Making Linux a Windows File Server)
• Advantage: no distance limitation
• Disadvantage: Speed and Latency
• Weakness: Security
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7. Network Attached Storage (NAS)
• Specialized storage device or group of storage devices providing
centralized fault-tolerant data storage for a network
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Clients
Servers Storage Devices

8. Types of Storage…
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Typical SAN Storage solution

9. Storage Area Network (SAN)
• A Storage Area Network (SAN) is a specialized,
dedicated high speed network joining servers and
storage, including disks, disk arrays, tapes, etc.
• Storage (data store) is separated from the processors
(and separated processing).
• High capacity, high availability, high scalability, ease
of configuration, ease of reconfiguration.
• Fiber Channel is the de facto SAN networking
architecture, although other network standards
could be used.
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10. SAN Benefits
• Storage consolidation
• Data sharing
• Non-disruptive scalability for growth
• Improved backup and recovery
• Tape pooling
• LAN-free and server-free data movement
• High performance
• High availability server clustering
• Data integrity
• Disaster tolerance
• Ease of data migration
• Cost-effectives (total cost of ownership)
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Difference between NAS & SAN
Traditional Differences

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Difference between NAS & SAN
Block Oriented Difference between NAS & SAN
The Wires being used:
• NAS solutions utilize TCP/IP based networks, such as Ethernet
• SAN solutions use Fibre Channel connections (Fiber/Copper)
The Protocols being used:
• NAS solutions use file level protocol (CIFS/NFS) and now also SCSI over IP called iSCSI
Protocol over standard Ethernet networks
• SAN solutions utilizes Fibre Channel encapsulated SCSI setups

13. THANK YOU……